Handbrake will probably still work if you compile it from source, but it seems like upstream isn't paying much attention to libdvdcss support.

The version in Debian's repo still works for me, anyway.

Assuming you mean the Beelink S12 (which is the first thing that comes up in a search for "n100 mini pc"), that's quite similar to my own computer specs, which can run just about any distro, with enough resources to spare for a VM or two. I don't think it's necessary to go really lightweight or pick something special. If there's a distro you're already familiar with and know you can do all of those things on, install that.

If you like Garuda, you could always try a different Arch spin which is lighter out of the box, like CachyOS or EndeavourOS.

I was quite satisfied with Debian Stable for a few years on at least two different laptops, and felt I had found my "forever distro", until I got a Framework laptop whose AMD graphics were quite buggy on it. In order to get rid of all the issues, I had to upgrade to Testing and install a mainline Liquorix kernel (and along the way, I briefly made a Frankendebian and fiddled with kernel parameters). While my years of experience with Debian and derivatives has prevented me from breaking anything, I do wish I didn't have to use all of this beta-quality software just to prevent games from freezing and crashing constantly, just because I bought "new" (about a year old) hardware.

I still want to keep Debian, because I've found nothing else that works quite as elegantly or stably, but I'm hoping to find ways to get the performance I need without Liquorix, and if something forces me to reinstall between now and the time Debian Trixie becomes stable, I'll probably give Fedora or KDE Neon another try.

Last time I used Elementary OS, it was great if you were only using the official apps, with insane degrees of polish, but things like LibreOffice were surprisingly hard to configure the way I wanted. That was a while ago, though.

Debian needs a better installer. It'd be awesome if it had something more akin to Fedora/RHEL's Anaconda, or even just made Calamares the default (so long as it didn't install every single locale available like their live inages currently do).

Another commenter suggested Tiny Core Linux and DSL2024, which are indeed as light as it gets, but you might find yourself limited in what you can do with them, and it's not necessary for those specs.

The next step up would be Q4OS Trinity and antiX. You should be able to get the Spotify app and your preferred web server running on either of those.

Debian 12 ships with the non-free-firmware repo enabled by default, including firmware-iwlwifi, but a few Broadcom cards, and maybe others, still require software in non-free if I recall correctly

I'm aware of FreeTube and PlasmaTube, which IIRC both require an Invidious instance. There was something called SMTube in the past, not sure if it still exists.

Nothing I'm aware of has both desktop and mobile version, but if anything there are more options for mobile YouTube clients; try NewPipe or Clipious.

Edit: SMTube does still exist. It does not require Invidious, but it does use tonvid.com.

Startendo DS (Dual Screen) Nine

Sure!

You're basically describing the Linux Standard Base, which was abandoned back in 2015 and the way it was handled was somewhat controversial.

But there is a lot of informal standardization between Linuxes, nonetheless.

Super glad it's still in production despite all the bullshit with Paramount+. Though I still wonder where it will be published...